Magnetic coils for inductors are currently manufactured in two ways. The first and most common method of coil manufacture is the wrapping of circular copper wire on a bobbin which is then placed on a magnetic core. The other method that is sometimes used is the wrapping of a rectangular copper strip on a bobbin as a spiral wound coil which is then placed on a magnetic core.
Coils formed by the first approach are quite readily fabricated but have numerous disadvantages which are, in part, overcome by strip wound coils. Thus, because the rectangular strip fits better or tighter on a bobbin, a larger amount of conductor may be wound on a bobbin and internal losses are reduced. Strip wound coils are easier to tap and have better thermal heat conductivity, as well, as, a lesser danger of arcing because consecutive turns lay next to each other rather than being displaced so that no large voltage exists between turns.
Both prior art wire wound and strip wound coils require bobbins which are disadvantageous both in coil winding and in coil use, and neither readily admit of any modification once a coil is completed.
The edge "winding" of a flat strip to form a helical coil is normally an expensive and time-consuming mandrill operation that militates against widespread application of such coils. (See the citations infra herein.)
The present invention, in extreme contrast comprises a process for forming such helical or a helix-wound coil for an inductor which has all of the advantages of a strip wound coil and additional advantages, as noted below, and further provides a simple and economical process of producing such a coil.